Characteristics of Life
Living things breathe, eat, and eliminate waste—this term describes all the chemical processes that keep an organism alive.
Metabolism
What structure surrounds all cells and controls what enters and exits?
The cell membrane — it acts as a protective barrier and gatekeeper
What is the shape of a DNA molecule called?
A double helix
What are white blood cells, and why are they important to the body?
White blood cells are part of the immune system and protect the body by fighting infections and attacking harmful invaders
What is the process that plants and some bacteria use to turn sunlight into sugar?
Photosynthesis
The ability of bacteria to resist antibiotics over many generations is due to this process.
Evolution (or natural selection)
What is the cytoplasm, and what does it do?
The cytoplasm is a jelly-like fluid inside the cell that holds the organelles and allows chemical reactions to happen.
In DNA, which base does adenine always pair with?
Thymine
Why are Darwin’s finches important evidence for evolution?
They showed how species can adapt over time — each finch had a different beak shape suited to the food on its island.
What is the role of decomposers in an ecosystem, and what’s an example of one?
Decomposers break down dead plants and animals, recycling nutrients back into the ecosystem. Examples include fungi and bacteria
TWhat do all organisms do to maintain stable internal conditions despite changes in the environment?
Maintain homeostasis — like keeping body temperature or pH balanced
What strong outer layer do plant cells have that animal cells do not, and what is it made of?
The cell wall — made of cellulose, it provides structure and protection.
What is a vesicle, and what is its job inside the cell?
A vesicle is a small sac that helps store or transport materials like proteins and waste within the cell
What is the main function of the circulatory system in the human body?
It transports oxygen, nutrients, and waste throughout the body using blood vessels
In an energy pyramid, which group is found at the bottom and why?
Producers which make their own energy through photosynthesis and provide energy to all other levels.
Some single-celled organisms can move toward helpful things or away from danger. What is this movement response called?
Response to stimuli
What are ribosomes, and what is their role in the cell?
Ribosomes are tiny structures that build proteins by translating genetic instructions from mRNA.
What are the two types of endoplasmic reticulum, and what are their functions?
Rough ER: Has ribosomes and helps make proteins.
Smooth ER: No ribosomes; makes lipids and helps detoxify the cell.
What is the term for a species’ role and position in its environment, including how it gets resources and interacts with other organisms?
Niche (every organism has a specific role that helps maintain balance in an ecosystem)
What happens to the amount of energy available as it moves up the food chain?
It decreases and only about 10% of the energy gets passed on to the next level; the rest is lost as heat.
Do scientists consider viruses living or non-living? Explain your reasoning.
Non-living. Viruses can’t carry out basic life processes like metabolism or reproduction without a host cell. (answers could vary, as there is debate)
What would happen to a cell if it didn’t have lysosomes, and why would that be a problem?
The cell would be unable to break down waste or damaged parts, causing harmful buildup and possible cell death.
DNA is made of smaller building blocks. What are these units called, and what three parts make them up?
Nucleotides which are made of a sugar, a phosphate, and a nitrogen base
Why is having genetic variation important for a species' survival when environments change?
More variation means a better chance that some individuals will have traits that help them survive and reproduce in new conditions.
How are photosynthesis and cellular respiration connected in living systems?
Photosynthesis makes glucose and oxygen, which are used in cellular respiration to make energy; cellular respiration returns carbon dioxide and water, which plants need for photosynthesis